Feat: check regexp before build (#3064)

Co-authored-by: Loyalsoldier <10487845+Loyalsoldier@users.noreply.github.com>

main.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strconv"
 	"strings"
@@ -71,6 +72,11 @@ func (l *ParsedList) toProto() (*router.GeoSite, error) {
 				Attribute: entry.Attrs,
 			})
 		case "regexp":
+			// check regexp validity to avoid runtime error
+			_, err := regexp.Compile(entry.Value)
+			if err != nil {
+				return nil, fmt.Errorf("invalid regexp in list %s: %s", l.Name, entry.Value)
+			}
 			site.Domain = append(site.Domain, &router.Domain{
 				Type:      router.Domain_Regex,
 				Value:     entry.Value,